Methods for cutting and raising submerged masses

ABSTRACT

A submerged mass is cut by repeatedly dropping a chopping tool thereon. The chopping tool is coupled to a hoisting mechanism carried by a floating platform and comprises a pair of flanges which have downwardly converging edges forming a pair of spaced cutting tips. A web extends transversely between, and is connected to, the flanges adjacent the cutting tips. The lower edge of the web is recessed to define with the cutting tips a pair of spaced impact points. The bottom edges of the tool are of bulbous configuration. A retrieval hook is dropped onto a section severed by the tool. The retrieval hook includes a pointed body portion and a grapple arm pivotally mounted to the body portion. The grapple arm is operable to swing outwardly of the body portion in response to penetration of the submerged mass by the pointed body portion. Subsequent lifting of the retrieval element causes the grapple arm to contact and lift the severed section.

llnited States Patent 1 Banjavich METHODS FOR CUTTING AND RAISINGSUBMERGED MASSES Inventor: Mark P. Banjavich, New Orleans,

Taylor Diving & Salvage Co., Inc., Bell Chasse, Plaquemines Parish, La.

Filed: Apr. 10, 1973 Appl. No.: 349,748

Assignee:

US. Cl. 225/1, 241/273 Int. Cl B26f 3/00 Field of Search 225/103, 1;241/273;

5/1894 Kennedy.... 2/1929 Vialetal.

Primary ExaminerAndrew R. Juhasz Assistant ExaminerLeon Gilden Attorney,Agent, or Firm-Burns, Doane, Swecker & Mathis [57] ABSTRACT A submergedmass is cut by repeatedly dropping a chopping tool thereon. The choppingtool is coupled to a hoisting mechanism carried by a floating platformand comprises a pair of flanges which have downwardly converging edgesforming a pair of spaced cutting tips. A web extends transverselybetween, and is connected to, the flanges adjacent the cutting tips. Thelower edge of the web is recessed to define with the cutting tips a pairof spaced impact points. The bottom edges of the tool are of bulbousconfiguration. A retrieval hook is dropped onto a section severed by thetool. The retrieval hook includes a pointed body portion and a grapplearm pivotally mounted to the body portion. The grapple arm is operableto swing outwardly of the body portion in response to penetration of thesubmerged mass by the pointed body portion. Subsequent lifting of theretrieval element causes the grapple arm to contact and lift the severedsection.

8 Claims, 10 Drawing Figures METHODS FOR CUTTING AND RAISING SUBMERGEDMASSES BACKGROUND AND OBJECTS OF THE INVENTION This invention relates tothe cutting of submerged masses and, more particularly, concerns methodsand apparatus for cutting and removing submerged metallic structures,such as sunken vessels.

Considering the extent to which most countries are dependant in some wayupon marine commerce and/or various other off-shore activities, such aspipeline laying and off-shore oil drilling, the importance ofmaintaining freely navigable waterways is readily apparent. The presenceof sunken vessels or other debris, which may restrict or prevent thefree passage of marine vessels, can produce considerable inconvenienceand economic harm.

Even when not obstructing marine travel, such debris can be detrimentalto the natural state of the environment.

As marine activity intensifies, the occurrance of collisions and otheroff-shore mishaps are likely to increase, resulting in the presence ofyet greater quantities of vessel-restricting wreckage. Thus, the needfor effective, economic and rapid techniques for the removal of sunkenwreckage will become progressively more critical.

Unfortunately, sunken structures are often too large to be convenientlyraised or lifted from the waterin one piece. lt is possible for a groupof divers, armed with underwater torches and other implements, to cutthe submerged structure into a number of individually raisable sections.In terms of the considerable time and expense involved, however, such anoperation is of limited utility at best.

It is, therefore, a general object of the present invention to minimizeor obviate problems of the types previously discussed.

lt is a further object of the invention to provide novel methods andapparatus for cutting a mass which is at least partially submerged.

It is a further object of the invention to provide novel methods andapparatus for cutting submerged masses, which methods and apparatus canbe utilized substantially independently of divers.

It is another object of the invention to provide such novel methods andapparatus which utilize the effects of gravity in producing cuttingforces.

It is another object of the invention to provide novel methods andapparatus for facilitating the cutting and- /l' removal of submergedobjects, such as metallic structures for example.

Still another object of the invention is to provide methods andapparatus for retrieving remote objects, such as submerged structures,by a self-actuating element.

BRIEF SUMMARY OF A PREFERRED EMBODIMENT At least some of the foregoingobjects are intended to be accomplished by the provision of a choppingtool cutting tips. A web extends transversely between and adjoins theflanges adjacent the cutting tips thereof. The lower edge of the web isupwardly concave to define with the cutting tips a pair of spaced impactpoints. The conversion edges on the concave edge include overlaymaterial defining a bulbous configuration at the bottom of the choppingtool.

In operation, the chopping tool is floated above the mass on a floatingplatform. The chopping tool is suspended over the mass by means of ahoisting mechanism carried by the floating platform. The tool is thenreleased for movement toward the mass such that the tool impacts andcuts the mass. The hole which is cut in the mass by the lower bulbousedges of the tool provides a clearance for the main body portion of thetool.

These steps are repeated, while shifting the chopping tool horizontallybetween successive cuts, until the mass is in a desired cut condition.

A visual guide can be provided for the operator of the tool by stringinga guide cable above the water surface in a direction generally parallelto a desired line of cut.

in deep water operations, the chopping tool may be confined within aguide frame which extends downwardly into the water. In this fashion,deflection of the chopping tool from its desired course of travel due tothe effects of underwater currents and the like will be resisted.

In order to isolate the hoisting mechanism from undesirable vibrationaleffects caused by repeated impacts of the tool with an underwater mass,a shock absorbing assembly is disposed between the chopping tool and thehoisting mechanism. Preferably, this shock absorbing assembly comprisesa plurality of vehicular or aircraft tires connected in series.

During operations involving the removal of a sunken In operation, theretrieval element is dropped onto a severed hull section such that thepointed body portion penetrates the outer plating of the hull. The bodyportion will penetrate the outer plating and will be abruptly haltedwhen the abutment plate engages the outer plating. As a result, thegrapple arm will swing outwardly to its extended position under its ownweight. By subsequently lifting the retrieval element, the grapple armwill be brought into contact with the underside of the outer plating.Further lifting of the retrieval element will result in the severed hullsection being lifted from the water bed. v

Once removed from the water, the severed hull sectionis placed on asuitable deposit station/The retrieval element is conveniently removedfrom the deposited hull section by removing the pivot pin of the grapplearm and detaching the grapple arm from the body portion.

THE DRAWING Other objects and advantages of the present invention willbecome apparent from the subsequent detailed description thereof inconnection with the accompanying drawings in which like numeralsdesignate like elements, and in which:

FIG. 1 is a schematic illustration of a chopping tool suspended over asubmerged structure, according to the present invention.

FIG. 2 is a side elevational view of the bottom portion of the choppingtool impacting against a submerged structure.

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2.

FIG. 4 is a longitudinal sectional view taken along line 4-4 of FIG. 2.

FIG. 5 is a schematic illustration depicting two embodiments of thechopping tool being suspended over submerged structures.

FIG. 6 is a schematic illustration, in perspective, of a chopping tooldisposed above a submerged hull and adjacent a guide cable according tothe invention.

FIG. 7 is a side elevational illustration of a chopping tool confinedwithin a guide frame, in accordance with the invention.

FIG. 8 is a plan view of a platform floatingly disposed over a submergedhull.

FIG. 9 is a side elevational illustration of a retrieval hook elementaccording to the invention.

FIG. 10 is an illustration, in perspective, ofa severed section of asubmerged hull being raised by the retrieval element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference toFIGS. 1 through 10 of the accompanying drawing, preferred method andapparatus aspects of the invention will be described in conjunction withthe cutting and removal of vessels or hulls which are submerged in abody of water.

In accordance with the invention, the hull 10, shown in FIG. 1 as beingsubmerged, is to be cut into individually raisable sections. This isaccomplished by the utilization of a chopping tool 20, a preferred formof which is illustrated in FIGS. 1 through 4.

The chopping tool is carried by a suitable hoisting mechanism, such as acrane 21 having a boom 21b. The hoisting mechanism is disposed above thehull being cut. For example, the hoisting mechanism may be mounted on afloating platform 23.

The chopping tool 20 is generally vertically elongated and I-shaped incross-section (FIG. 3). This tool 20 comprises a pair of flange plates22 and an interconnecting web plate 24. The flange plates extendgenerally parallel and each flange includes side surfaces 25 and endedges 26. The lower portions of the end edges 26 converge downwardlysuch that the flanges define a pair of spaced cutting tips 30 (FIG. 4).

An overlay 32, preferably comprising a highly ductile material, such asnickel for example, as opposed to a brittle material, is provided alongthe bottom edge of each flange 22. The sides of this overlay materialconverge downwardly from the side surfaces 25 of the associated flange(see FIG. 2) to define a generally pointed cutting edge 34. Thus, in thepreferred embodiment of the invention, the bottom edge of each flange22, as defined by the overlay 32, is configured as a pointed, generallyV-shaped cutting edge 34 (FIG. 4).

It will be apparent that the cutting tips 30 and the recessed web 24define a pair of spaced impact points 42 separated by the recessedcutting edge 40. Thus, upon being dropped or propelled onto a submergedmass, the impact forces of the chopping tool will be concentrated atthese two points. In this fashion, penetration of the mass at one orboth of the impact points will be facilitated. Continued downwardmovement ofthe chopping tool through the submerged mass will enable therecessed edge 34 to progressively cut through that portion of the massbetween the impact points. It will be understood that the curvedrecessed edge aids in cutting curved or angular surfaces, such asshafts.

The I-shaped structure of the chopping tool, wherein a pair of flanges22 are interconnected by a perpendicular web 24, provides an arrangementwherein the flange and web elements reenforce one another to preventtwisting or bending of the tool.

Significantly, the overlay portions 32 and 36 form bulbous, or enlargededges at the bottom of the chopping tool 20 (See FIG. 3). That is, thebottom end edges of the chopping tool are enlarged relative to the maintool body thereabove. Such a bulbous configuration facilitates thepenetration and removal of the chopping tool from a mass being cut. Forexample, and as viewed in FIG. 4, when the chopping tool 20 is droppedupon and penetrates a submerged steel structure 44, a hole 46 is cut inthe structure. Since the bottom edges of the tool are bulbous, the hole46 will be significantly larger than the main body portion of thechopping tool. The resultant clearance which is provided between thetool and the severed edges of the structure allows the flanges 22 andthe web 24 to pass through the hole without being significantly resistedby frictional contact with the severed edges.

Bladed chopping tools which may be constructed in accordance with theteachings of this invention can vary in configuration depending upon thetypes of submerged masses to be cut. For example, and as shown in FIG.5, a relatively wide chopping blade 50 is employed to cut a submergedstructure 52 having a relatively thin frame and few decks. On the otherhand, a relatively long and heavier chopping blade 56 would be employedto cut a structure 58 having a thick frame and many decks.

In the latter case, it will be apparent that hulls having several decksrequire a longer cutting blade and greater downward momentum to insurecomplete penetration. In order to produce sufficient momentum, thechopping tool 56 is heavier than the tool 50 and is suspended above thewreck 58 by a greater distance than that required of the smaller tool50.

When a sunken vessel is to be cut into sections, it is desirable thatthe vessel be cut along its transverse and longitudinal bulkheads. FIG.6 depicts a sunken hull 60 having a transverse bulkhead 64. An imaginaryreference line 62 is shown in phantom along the outer plating of thesubmerged vessel. This line 62 corresponds to the location of thebulkhead 64. Since it may be necessary to drop the chopping tool in anumber of repeated chopping steps, it might be difficult for theoperator of the hoisting mechanism to observe the submerged vessel toproperly re-position the tool 20 for successive drops.

In accordance with the invention, a visual reference, corresponding tothe reference line 62, is provided. Such a visual reference may bedefined by a guide line, such as a cable 66, which is strung between apair of sunken pilings 68. The guide cable 66 is disposed above thewater surface and is oriented parallel to the reference line 62.

Thus, during repeated droppings of the chopping tool, an operator willbe afforded a visual reference guide afforded by the cable 66 forproperly re-locating the tool 62.

The chopping tool may be moved horizontally after successive cuttingsteps in any suitable manner, as by shifting the crane 21, or by reelingand unreeling conventional mooring cables 74 by means of mechanicalwinches 72 to alter the position of the platform 23 (FIG. 8). It mayalso be possible to align the crane 21 relative to the cutting line 62such that the chopping tool may be shifted by merely pivoting the boom21b.

During such horizontal shifting of the cutting tool 20, the tool ispreferably shifted so as to overlap approximately one-half its widthwith each successive cut.

it may be desirable, especially in deep water operations, to positionthe chopping tool within a vertically disposed guide frame 76 asillustrated in FlG. 7. If a crane 21 is employed, the guide frame 76 maybe connected at the end of the boom 21b and supported by suitablebracing structure 77. The guide frame 70 confines the chopping toolduring its downward motion and resists the effects of underwatercurrents and the like which might otherwise tend to deflect the tool.

In order to isolate the hoisting mechanism from the vibrational effectsof the chopping tool, the present invention features the provision of ashock absorbing assembly 78. As may be seen in FIG. 1, the shockabsorbing assembly 78 is in the form of a plurality of resilientelements 79, preferably conventional vehicular or aircraft tires,connected in series. Tires such as these are relatively inexpensive andeasily obtainable. The tires may be interconnected in series by means ofcables 81,

with the lowermost cable being suitably coupled to the chopping tool.

Once a section 69 of the hull 60 has been disjoined, or severed, it maybe suitably retrieved. In accordance with this invention, a novelretrieval hook element 80 is utilized (FIG. 9). This retrieval hook 80includes a pointed body portion 82 having an abutment plate 84 attachedto its upper end. A grapple arm 83 is pivotally mounted within a pocket86 of the pointed portion 82 by means of a removable pivot pin 88. Thisarm 83 is pivotal between a folded position wherein it is nested withinthe pocket 86, and an extended position wherein a stop shoulder 90 onthe arm 83 abuts a limit surface 92 of the pocket 86, as shown in FIG.9.

The retrieval hook 80 is arranged such that, upon being droppeddownwardly onto a submerged hull for example, with the arm 83 in afolded position, the pointed portion 82 penetrates the outer hullplating 93. When travel of the hook 80 is abruptly halted, such as bycontact of the abutment plate 80 with the outer plating 93, the arm 83will swing outwardly, under its own weight, to an extended positionbelow the outer plating. Subsequent lifting of the retrieval hook by ahoisting cable 90, attached to an eyelet portion 92 of the hook element,causes the grapple arm 83 to be raised into contact with the undersideof the outer plating. In this manner, a firm coupling between theretrieval hook 80 and the severed section of the wreck will be effected.

When the severed hull section 69 has been lifted from the water andtransferred to a suitable deposit station, the pivot pin 88 is removedfrom the hook. ln this fashion, the grapple arm 83 can be detached toenable the hook 80 to be freed from the hull.

OPERATION When it is desired to cut and remove a submerged structure,such as the sunken hull 60, a chopping tool 20 is suspended above thewreck. This may be accomplished by mounting the chopping tool on thecrane 21, floating the crane upon the platform 23, and suspending thetool 20 over the side of the platform.

Depending upon the size and configuration of the sunken hull to be cut,an appropriate type of chopping tool 20 is selected. Thus, for arelatively large hull 58 having numerous decks, as shown in FIG. 5, thelong, heavy, narrow chopping blade 56 will be employed. On the otherhand, a shorter, wider and lighter chopping blade will be utilized forsmaller hulls 52.

As noted previously, it is desirable to disjoin the hall along thebulkheads thereof.'To enable an operator to maneuver the tool along apath corresponding to the location of the bulkhead, a guide cablearrangement may be deployed. Thus, a pair of pilings 68 are driven, orotherwise placed, into the water bed. A cable 66 is then strungthereacross so as to be disposed above the water surface and ingenerally parallel alignment with the imaginary reference line 62corresponding to the location of the transverse bulkhead 61.

- The chopping tool 20 is thereupon suspended over the side of theplatform 23'adjacent to, but spaced from, the guide cable 66. At thispoint, the tool is released for movement toward the hull 60. This ispreferably accomplished by merely letting-loose the hoisting cablecarrying the tool such that the tool falls by gravity toward the hull.

Up to this point, the platform 23 has been anchored in place by themooring cables 74. To reposition the chopping tool 20 for a subsequentchopping step, the

' platform 23 may be horizontally shifted by appropriate actuation ofthe winches 72. Alternatively, the tool may be shifted by relocating thecrane 21 relative to the platform 23. Still further, if the crane 21 isaligned parallel to the reference line 62, the chopping tool may beproperly shifted by pivoting the boom 21b.

During horizontal shifting movement of the chopping tool 20, theoperator is able to maintain the chopping tool in proper alignmentrelative to the reference line 62 by observing the visual guide cable 66and positioning the tool accordingly.

It is noted that in deep water operations it may be advantageous tolocate the tool 20 within the guide frame 76 (FIG. 7) to assure that thetool is not unduly deflected from its desired downward path of travel byunderwater currents.

After the chopping tool has been shifted by an appropriate amount,preferably by one-half of its width, it is subjected to a subsequentchopping drop.

This operation is repeated until an independently raisable section ofthe hull has been severed.

When it is desired to remove the severed section 69 of the hull from thewater, a retrieval operation may be initiated, preferably by theretrieval hook element 80. Accordingly, the retrieval hook, connected atthe end of a hoisting cable 90, is dropped downwardly upon the severedsection 69, with the grapple arm 83 in a folded posture. When the knifeportion 82 of the retrieval hook penetrates the outer plating 93 of thesevered section and is abruptly halted, as by engagement of the abutmentplate 84 with this outer plating, the grapple arm 83 will swingoutwardly about its pivot pin 88 under the influence of its own weight.

Subseqnent lifting of the retrieval hook 80 will bring the grapple arm83 into contact with the underside of the outer plating. Further liftingof the retrieval hook will raise the severed section from the water bed.As is depicted in FIG. 10, mud and the like which may have accumulatedwithin the hull, will be free to flow outwardly from the severed section69 as it is being raised.

While the chopping tool has been described herein in conjunction withthe cutting of a submerged hull, it will be apparent that the tool maybe employed to cut almost any type of structure or debris. Moreover, thetool may be utilized to cut into other masses, such as a water-bed inmining or dredging operations and the like.

It should also be apparent that the retrieval hook 80 is suitable forgrasping and lifting any penetrable structure which will accomodateoutward swinging of the grapple arm 83.

MAJOR ADVANTAGES AND SCOPE OF THE INVENTION The concept of cutting asubmerged mass by repeated blows from a downwardly directed choppingtool affords a simplified, yet effective, cutting operation whichutilizes gravity for producing the necessary cutting forces.

These forces will be effectively concentrated at one or two points onthe mass being cut, due to the novel configuration of the cutting toolwhich is characterized by a pair of spaced impact points separated by arecessed cutting edge.

The lower edges of the cutting tool, being bulbous in shape, are able tocut a hole in the mass which is larger than the main tool body. As aresult, there will be minimum frictional resistance exerted upon thetool in passing through the mass.

The generally l-shaped configuration ofthe chopping tool exhibitssignificant strength to effectively resist bending or twisting of thetool.

The employment of a guide line arrangement above the mass being cutaffords a simple, yet effective means of providing a visual guide for anoperator.

An effective manner of resisting deflection of the cutting tool isprovided by the guide frame structure which 6 confines the chopping toolto substantially vertical travel through the water.

Vibrational shock which results from the tool striking the mass beingcut is substantially isolated from the hoisting mechanism by thesimplified, yet effective,

shock absorbing assembly 78.

5 The retrieval hook 80 of the invention is ofsimplified constructionand is essentially self-actuating. Moreover, the hook is capable ofconvenient disassemblage to facilitate removal of the hook from astructure being retrieved.

Although the invention has been described in connection with a preferredembodiment thereof, it will be appreciated by those skilled in the artthat additions. modifications, substitutions and deletions notspecifically described may be made without departing from the spirit andscope of the invention as defined in the appended claims.

What is claimed is:

1. A method for cutting a mass which is submerged within a body ofwater, said method comprising the steps of:

positioning a chopping tool over said submerged mass;

releasing the chopping tool for downward movement toward said mass;

impacting said chopping tool against said mass to penetrate and cut saidmass;

raising said tool by means of a hoisting mechanism connected to saidtool; and

repeating said steps of positioning, releasing, impacting, and raisinguntil the mass is in a desired cut condition.

2. A method for cutting a mass which is submerged within a body ofwater, said method comprising the steps of:

positioning a chopping tool over said submerged mass; releasing thechopping tool for downward movement toward said mass such that saidchopping tool impacts and cuts through said mass, including cutting anopening in said mass by bulbous lower edges of said chopping tool toproduce a clearance for the main body portion of said chopping tool,raising said tool by means of a hoisting mechanism connected to saidtool; and repeating said steps of positioning, releasing, and raisinguntil the mass is in a desired cut condition.

3. The method according to claim 1 wherein said step of impacting thechopping tool against the mass further comprises the steps of:

impacting spaced cutting tips formed by the downwardly converging edgesof the flanges of a structural member against the mass to penetrate themass; and concurrently impacting an arcuate. concave upward cutting edgeformed by a web connecting the flanges against the mass to cut throughthe mass. 4. The method according to claim 1 and further comprising thestep of:

insulating said hoisting mechanism from forces developed incident to themovement of said chopping 5 tool by interposing resilientshock-absorbing means between said chopping tool and a hoistingmechanism carrying said chopping tool.

5. The method according to claim 1 wherein said step of repeatingcomprises the step of shifting-said chopping tool generally horizontallyrelative to said mass such that said tool cuts said mass along a desiredcutting path.

6. The method according to claim 5 and further including the step oflocating a guide line above the water surface and aligning the guideline generally parallel to the desired cutting path to provide a visualguide for orienting the chopping tool.

7. The method according to claim 1 wherein said step of releasingcomprises the step of confining said tool within a movable guide framemeans disposed in said water and directed toward said mass.

cutting an opening in said structure by the bulbous bottom cutting edgeof the chopping tool to produce a clearance for the main body portion ofsaid chopping tool.

1. A method for cutting a mass which is submerged within a body ofwater, said method comprising the steps of: positioning a chopping toolover said submerged mass; releasing the chopping tool for downwardmovement toward said mass; impacting said chopping tool against saidmass to penetrate and cut said mass; raising said tool by means of ahoisting mechanism connected to said tool; and repeating said steps ofpositioning, releasing, impacting, and raising until the mass is in adesired cut condition.
 2. A method for cutting a mass which is submergedwithin a body of water, said method comprising the steps of: positioninga chopping tool over said submerged mass; releasing the chopping toolfor downward movement toward said mass such that said chopping toolimpacts and cuts through said mass, including cutting an opening in saidmass by bulbous lower edges of said chopping tool to produce a clearancefor the main body portion of said chopping tool, raising said tool bymeans of a hoisting mechanism connected to said tool; and repeating saidsteps of positioning, releasing, and raising until the mass is in adesired cut condition.
 3. The method according to claim 1 wherein saidstep of impacting the chopping tool against the mass further comprisesthe steps of: impacting spaced cutting tips formed by the downwardlyconverging edges of the flanges of a structural member against the massto penetrate the mass; and concurrently impacting an arcuate, concaveupward cutting edge formed by a web connecting the flanges against themass to cut through the mass.
 4. The method according to claim 1 andfurther comprising the step of: insulating said hoisting mechanism fromforces developed incident to the movement of said chopping tool byinterposing resilient shock-absorbing means between said chopping tooland a hoisting mechanism carrying said chopping tool.
 5. The methodaccording to claim 1 wherein said step of repeating comprises the stepof shifting said chopping tool generally horizontally relative to saidmass such that said tool cuts said mass along a desired cutting path. 6.The method according to claim 5 and further including the step oflocating a guide line above the water surface and aligning the guideline generally parallel to the desired cutting path to provide a visualguide for orienting the chopping tool.
 7. The method according to claim1 wherein said step of releasing comprises the step of confining saidtool within a movable guide frame means disposed in said water anddirected toward said mass.
 8. A method of cutting a mass which is atleast partially submerged in a body of water, the method comprising thesteps of: positioning over the structure a chopping tool having a mainbody portion and a bottom cutting edge, the cutting edge being ofbulbous configuration relative to said main body portion; releasing thetool for downward movement toward the structure, and cutting an openingin said structure by the bulbous bottom cutting edGe of the choppingtool to produce a clearance for the main body portion of said choppingtool.